1cby

DELTA-ENDOTOXIN


Although, 1cby is a 1 chain structure, the biological relevant molecule for 1cby can be assembled from the contents of the deposited coordinates by the application of crystallographic symmetry operations to give a dimer. It can be downloaded. A remarkable similarity is observed between the structures of the endogenously cleaved Cyt2Ba monomer (gray, 2rci) and the corresponding region (red) within the inactive protoxin dimer of Cyt2Aa (this entry; monomers A and B of Cyt2Aa shown red and blue, respectively, the N- and C-termini are shown in spacefilling representation). Each monomer of Cyt2Aa (1cby), consists of an additional β-strand at its N-terminus and an additional α-helix at its C-terminus compared to the cleaved Cyt2Ba. The dimer interface of Cyt2Aa is held together by the intertwined N-terminal strands from both monomers. The cleavage of Cyt2Aa removes the N- and C-terminal segments, prevents dimer formation and releases an  active toxin monomer. Similarly, in Cyt2Ba the proteolysis causes the removal of 34 amino acids at its N-terminus and 28 or 30 residues at its C-terminus forming the crystallized toxic monomer.

About this Structure
1CBY is a 1 chain structure of sequence from Bacillus thuringiensis. Full crystallographic information is available from OCA.